When a metallic surface is illuminated with light of wavelength $\lambda$,the stopping potential is $V$. When the same surface is illuminated by light of wavelength $2 \lambda$,the stopping potential is $\frac{V}{3}$. The threshold wavelength for the metallic surface is:

When a certain metallic surface is illuminated with monochromatic light of wavelength $\lambda$,the stopping potential for photoelectric current is $6V_0$. When the same surface is illuminated with light of wavelength $2\lambda$,the stopping potential is $2V_0$. The threshold wavelength for the photoelectric effect for this surface is:

$A$ photon of energy $8 \ eV$ is incident on a metal surface of threshold frequency $1.6 \times 10^{15} \ Hz$. The maximum kinetic energy of the photoelectrons emitted (in $eV$) is: (Take $h = 6 \times 10^{-34} \ J \cdot s$ and $1 \ eV = 1.6 \times 10^{-19} \ J$)

When a photon of energy $6 \ eV$ is incident on a metal surface with a work function of $2.1 \ eV$,what is the stopping potential of the emitted electrons in $V$?

$A$ beam of electromagnetic radiation of intensity $6.4 \times 10^{-5} \; W/cm^{2}$ is comprised of wavelength $\lambda = 310 \; nm$. It falls normally on a metal surface (work function $\varphi = 2 \; eV$) of surface area $1 \; cm^{2}$. If one in $10^{3}$ photons ejects an electron, the total number of electrons ejected in $1 \; s$ is $10^{x}$. Then $x$ is: $(hc = 1240 \; eV \cdot nm, 1 \; eV = 1.6 \times 10^{-19} \; J)$

Light comprising three wavelengths $310 \ nm$,$455 \ nm$,and $620 \ nm$ is incident on a surface separating two media at an angle of $45^o$. The refractive index for the $455 \ nm$ light is $\sqrt{2}$. If a metal plate with a work function of $1.2 \ eV$ is placed in the second medium,what is the maximum kinetic energy of the electrons emitted from the metallic plate in $eV$?